Rust preventive compositions containing monoamidocarboxylic acids



2,190,179 Patented Apr. 30, 1957 RUST PREVENTIVE COMPOSITIONS CONTAININGMONOAMIDOCARBOXYLIC ACIDS John D. Spivack, Craustou, Robert M. Pines,Providence, and Harry Kroll, Warwick, R. 1., assignors to Gcigy ChemicalCorporation, a corporation of Delaware No Drawing. Application July 27,1953, Serial No. 370,619

16 Claims. (Cl. 252-392) This invention relates to rust preventiveoleaginous compositions. More particularly the invention relates to theuse of certain nitrogenous corrosion or rust inhibitors in compositionscontaining predominantly an oleaginous vehicle, and which compositionsmay become contaminated with water or steam.

The prevention of rust formation is particularly important in theprotection of metal surfaces, particularly ferrous surfaces, where suchsurfaces are to be lubricated in the presence of contaminating moisture.Moisture may enter lubricating systems of land and marine turbineengines, for example, by leakage through steam glands and throughwater-cooled heat exchangers or simply by condensation from theatmosphere. The presence of rust is injurious because it causesexcessive wear of gears and bearing surfaces, and may also clog thehydraulic governor system, which last result may lead to dangerousoperating speeds. Furthermore, the presence of rust has been shown toincrease the rate of oxidative breakdown of the lubricant. Theprevention of rusting is also essential in the moving parts of hydraulicsystems generally, such as hydraulic bailing machinery, presses, etc.important applications of rust preventive compounds are in preservativeoils, slushing oils, flushing oils, etc.

A great many materials have been proposed for the prevention of rustformation of metal surfaces, however, relatively few have beenapplicable in practice for the protection of lubricant systems becausemost are deleterious to the lubricant, the lubricant system or aredisadvantageous in some other way. It has been proposed to add variouscarboxylic acid amides to hydrocarbon oils either for rust prevention orin order to improve the film strength and adhesion to metals. U. S.Patent No. 2,462,358 incorporates an acetoacetyl amide with an acylresidue which is of a higher fatty acid or naphthenicacid, such asC17H37CONHC2H4NHCOCHzCOCHa, for the latter purpose. And U. S. Patent No.2,403,293 discloses the incorporation of oleic monoamide of ethylenediamine or of polyethylene polyamines, purportedly a rustproofingcomposition. There has also been issued U. S. Patent No. 2,270,113 onesters of glycine or alanine added to oils to inhibit corrosion.

According to the present invention, it has now been found that thecorrosive effect of lubricating oils and greases (oleaginous vehicle)upon bearing surfaces, gears and other metallic parts in the presence ofwater may be prevented by the incorporation in said oleaginous vehicleof a small amount of a class of compounds which are monoamidocarboxylicacids and their salts in which a high molecular weight aliphatic acidresidue is bound to the amide nitrogen, and more specificallycharacterized below. Such compounds, it has been determined on ascientific basis, effectively prevent the rusting of metal surfaces,particularly those of ferrous metals, upon exposure to water or steam,when used in small amounts in lubricating compositions. These additivesmoreover prevent rusting without influencing the lubricant actiondisadvantageously.

Other 2 The rust preventive compositions of this invention consist ofmajor amounts of an oleaginous vehicle and a minor amount of the classof compounds monoamidecarboxylic acids having the empirical formulawhere R1 represents an aliphatic carboxylic acid residue of CaC-24, oralkyl phosphoryl, alkyl phosphonyl, alkyl sulfonyl wherein the alkylradical has this same number of carbon atoms; where R2 represents analkyl, hydroxyalkyl, phenyl group or H; R3 represents an alkyl,carboxyalkyl groups or H; n represents 0 or 1; X represents H or groupscapable of forming salts with the carboxylic acid groups such asammonium or substituted ammonium groups, e. g. organic amines, metals,etc.

The higher molecular weight acid in the amide group can be any of thehigher fatty acids, either saturated or olefinic unsaturated, of thischain length, such as-from caprylic acid through behenic in thesaturated series. Many of these higher saturated and unsaturated fattyacids occur as glycerides in fats and oils in nature or as esters ofmonohydric alcohols in waxes. But higher molecular weight aliphaticacids Within this general class which do not occur naturally, such asthe mixed carboxylic acids in oxidized liquid or solid hydrocarbons, canbe used. It will be understood that mixed acids can be used of any ofthese sources, i. e., mixed higher fatty acids, or the synthetic mixedaliphatic acids from hydrocarbon oxidation, or mixtures of each, etc.

The members of this class of compounds, which are the additives of thepresent invention, may be regarded as derivatives of the natural andsynthetic amino acids, for example derivatives of glycine, a or 13alanine, sarcosine, aspartic acid, glutamic acid, leucine and otherbetter known amino acids. These amidocarboxylic acids and their saltscan be prepared in a number of ways, e. g. as outlined in Equations A orB.

o B. R. o a, Rdo1++oH oHi ..000K Q RilN-t'JEKOHzhCOOK o In alkaliRti'lN-(JHGJHQJJOOH (B) in The members of this class of compounds can beused alone in an oleaginous vehicle or -solvent. The latter may betermed the lubricating oil or -grease when the designation is thought ofbroadly. When used in an oleaginous vehicle, these compounds should besoluble, miscible or dispersable in the vehicle. If the amidocarboxylicacid or its salts is not soluble therein, at least in the percentageadded solubilizers may be added which bring this about; a suitable agentfor this purpose is disclosed subsequently. The term oleaginous vehicleas used in the specification and claims includes mineral lubricatingoils derived from the refinement of petroleum or any of the so-callednonmineral oils, such as animal, vegetable oils, fats, the syntheticpolyesters or organic acids, polysiloxane, polyalkylene glycols,polyolefins, also the rust-proof bases which may be used as the mediumof application of rust preventive additive to the metal surface.

qmem m s fl helu t qa s. asevwi libel rsr. ferredfor specificapplications while other members will be preferred for other technical,industrial applications, where rust prevention is the objective. For itis obvious that the type of .lubricating oil or grease for suchsur vfaces as machine parts, piston rings machine guns, light arms; s i'wr'ne fths q nsra s draul c baling machinery; or presses, metal'drurns,etc., will vary greatly.

Some members of this class of compounds, namely the monoamidocarboxylicacid additives, will be preferred a d ersl i l F b 1 ie s m are achievedin practice by specifying that.

11 lubricant pass "certainru'stpreventive nd One of .Z'tli rustpreventive tests idelyi'used is 'the':Static"Water, Drop .Coi"ro sioneyeloped by Zisman'etaliand,des i edinflndns trial and Engineering:Chemistry, 'fvoluine "El-[page fl. f '(19 4 9 Brjiyfthisjtestinvolves'Qobserving rusting at140 F. in th p esericjeoftadropfof'fdistilled Waterin I thedir'nple of atr'ia'ngular' cold-rolledsteelspecimen' immersetl in the test oil. adequately rust inhibitedoilwill"pr eve nt frusti'n'g 'for severalfdays' while a straightmirieraljbt fwill' permit 'rusting' within several hours. HTh""den-iulsibility properties of lubricating oils are charf f;'zedfbytheFedral' Standard Stock Catalog method dated .NQvember" l5,"19i8, and entitled Emil sion (Lu'brf' atingQO Briefly, this testinvolvesmi ing'" 40 millzlitersof water and "41) "illilitersflofest.oil. at 130 F. or 180 F. understanda'rd eenaitiens anu; observing theseparation of oil and water phases at the" test temperature. f Theftesttemperature selected is usually 130 F. for light viscosity turbine oilsup. to about 500 1 Saybolt Universal seconds at 100 F. The U. S. Navyspecifies ;that 2190Tgrade turbine oils separate from water inthis testwithin 30 minutes and have not more than 3 m'illiliters'of'anintermediate oil and water phase at this time in order to comply withNavy 140l5 Specificatioiis This criterion of demulsibility is widelyadopted by turbinj'e' oil producers End: consumers.

The amount of corrosion inhibitor incorporated in the finishedlubricating composition may be vervsrnall amounts of the order ofO.0125% 1 base d on the total finished'oil lubricant; b eing sulficientto secure metallic corrosion preventiongmoreparticularly where the.surface is terrous innature. Greater amounts may be added as f r' i e sfli smea s' and P =9ncm wn;a

of the more important usespf the. various types mono-"carboxylic acidsof the present invention, in turbine lubrication; are thefollowing;Metal 7 d forming operations, gears and bearings under. v con tions ofextreme ppressureprnotor oil for internal combustion engines, and tap"cylinder lubricants. v p

The. followingexamples are offered to illustrate, but not to lir njihthemanner in .whicl the present invention may bepra 'i'sed.

"' eM LE 7.5. gramsof glycine was dissolvedin 100- milliliters of watercontaining 4.0 grams of sodiumhy'dro'xide. "30.2 ams of .stearoylchloride and 50-milliliters ofaqueous sodium hydroxidewo'ntaining 4.0gramsof sodiunif 113ll 7.

terisls. era imultensuusly ddsdlqihe llialineslr iue.

solution over a period of 20 minutes while maintaining the temperatureof the mixture at about 25 to 35 C. The reaction mixture became turbidand viscous and was stirred for an additional hour. It was thenneutralized to pH 2 with dilute hydrochloric acid. The precipitatewhich, formed was. filtered, washed with-water, andair-- dried for twodays. It weighed '3 1.6 grams- Recrystallization from ethyl acetateyielded a white product which melted at 123 C. and had a neutralizationecpgivalentwei-ght of The heore a 'nei t e izati n u val n weight of(N-stearoyl) glycine is 341.

The product described inthe example was tested for its rust preventiveproperties by dissolving it in a solventrefined and filtered.non-additive turbinegrade lubricating mineral oil of 150 Saybol-tUniversal seconds viscosity at F. and subsequently testing this oilsolution by the Static Water Drop Corrosion Test? described above.

EXAMPLE II 10.2 grams, 0186percent sareosineland 6.1 grams of magnesiumoxide were dispersed in 200 milliliters of water and 30.2 grams stearoylchloride was. added dropwise over, a period. of thirty-five minutes. Thereaction mixture was stirred for an additional 1.5 hours at roomtemperature and then .made acid topH 2 With dilute hydroohloric acid.The precipitate which formed was filtered, washedwith water andair-dried. The yield .Was.

100 Fuand subsequently testing this oilsolutionby the Static Water DropCorrosion Test and Emulsion Test described above.

' EXAMPLE III 11.8 grams of 75.5 percent sodium sarcosine wasdissolved.in. 100.. milliliters of water and 21.7 grams of lauryLchloride and 54.grams of aqueous sodium hydroxide containing 4.0 grams of sodiumhydroxide were added dropwisesimultaneously over a period of 30minutes.- On-..acidification ofthe mixture to pH 2 with 6 N hydro--chloric .acid a buttery...white solid-separated which was extracted.with ether; ..the ethereal solution was thereupon On" removal of;ether,..the residue .Weighed2L3 grams andhad aneudried over:anhydroussodium sulfate.

tralization .equivalenrw'eight of 275K The theoretical neutralizationequivalent weight for .(NJauroyl) sarcosine isr.27.l.."Aftencr'iystallizationfromh-hexane (N- lauroyllsarcosinehad a meltingpointv of 45th 47C;

Theeproduct described in theexample was tested-foritstrustlpreventiveproperties by dissolving it in a solvent refined and filterednon-additive turbine grade lubricating mineral oil of Saybolt Universalseconds viscosity at 100%. F.a=(37.8. C.) and. subsequently testingthisoil solution by the .fStatioWater Drop Corrosio-nTest described 1 aboveEXAMPLE IV 5.4 grams of m alanine was dissolved in 62.7 milliliters of1l00 N'NaOH solution 18.5 grams of stearoyl chloride and 65 millilitersof; l.00 -N aqueous caustic soda were added dmpvviseQsimultaneously.over a period of 25 minutes. The reaction mixture was stirred for anadditional 30 minutes and then acidified with 6 N hydrochlori'c acid topH 2. 7 The precipitate which formed was filtered, washed with water andallowed to air-dry, yield ing 2l'l3 granis' ofa white solid. Afterrecrystallization successively from acetone and carbon. tetrachloride,the

isolated (N-stearoyl) t1 alanine melted at lOS-IIO". C. and had aneutralization equivalent weight of 360. The

theoretical neutralization equivalent weight of (N-stearoyl) a alanineis 356.

The product described in the example was tested for its rust preventiveproperties by dissolving it in a solventrefined and filterednon-additive turbine grade lubricating mineral oil of 150 SayboltUniversal seconds viscosity at 100 F. and subsequently testing this oilsolution by the Static Water Drop Corrosion Test and Emulsion Testdescribed above.

EXAMPLE V 8.9 grams of S alanine was dissolved in 100 milliliters ofwater containing 4.0 grams of sodium hydroxide. 30.2 grams of stearoylchloride and 25 milliliters of aqueous sodium hydroxide containing 4.0grams of sodium hydroxide were added dropwise simultaneously over aperiod of thirty minutes. The reaction mixture was stirred for anadditional hour at room temperature and then made acid to pH 2 withdilute hydrochloric acid. The precipitate which formed was filtered,washed and air-dried, but since it showed a considerable ash on ignitionwhen tested, it was redissolved in 500 milliliters of aqueous alkalicontaining 200 milliliters of 1.0 N sodium hydroxide in which it wasclear when hot. This solution was also cooled to room temperature, thenmade acid to pH 2 as had been done in a prior step. The precipitatewhich formed was filtered, washed with water and airdried. The driedprecipitate weighed 36.0 grams and had a neutralization equivalentweight of 368. The theoretical neutralization equivalent weight of(N-stearoyl) 8 alanine is 356. On recrystallization from ethyl acetatethe purified (N-stearoyl) [-3 alanine melted at 1l9-l20 C.

The product described in the example was tested for its rust preventiveproperties by dissolving it in a solventrefined and filterednon-additive turbine grade lubricating mineral oil of 150 SayboltUniversal seconds viscosity at 100 F. and subsequently testing these oilsolutions by the Static Water Drop Corrosion Test described above.

Solubilization of some of these amidomonocarboxylic acids synthesized inthe above examples was eifected when required by the addition of asolubilization agent which per se in oil solution had little if any rustpreventive properties. The agent used was a commercially availableprimary, aliphatic amine, which has the tertiary-alkylamine structure,the tertiary alkyl groups having from 18-24 carbon atoms. Emulsion testswere also run on some of these oil blends. The test results are given inTable I.

It is evident that the rust preventive effectiveness of lubricating oilsolutions of the monoamidocarboxylic acids is much improved over" thebase oil alone or with the solubilizer in it. It is also evident thatthe monoamidocarboxylic acids are qualitatively superior in rustpreventive effectiveness than a typical high molecular weight fattyacid, such as stearic acid or the latter admixed with this identicalsolubilizer.

While the utility of our invention is illustrated by reference to itsadaptability to turbine grade mineral lubricating oils, it is to beunderstood that this is intended to be merely illustrative and not alimitation of the scope thereof. Thus our invention is applicable toother oils, whether or not comparable in specification and origin,including emulsifiable soluble oils, liquid fuels, greases, and ingeneral compositions in connection with which the water-corrosion of thecontaining system is to be avoided.

Having disclosed the nature of our invention and the manner in which itmay be practiced, what we claim and desire to protect by Letters Patentare the following:

1. A rust preventive oleaginous composition adapted for use in thepresence of water, in systems containing metal susceptible of corrosionby water, comprising an Table I.'Rust preventive and demulsibilityproperties of aminocarboxylic acids in lubricating oil Static Water Ex-Wt. Wt. Emul- Drop Additive (A) ample Per- Percent sion Corrosion No.cent Primene Test Test (A) (A) J MR 1 Time to Rust (Hours) Base Oil None None Pass Less than Stearic Acid None Pass Do. "Primene JMR 0. 20Pass Dc. Stearic Acid and Pri- 0. 20 Less than mene JMR. 2. (N-stearoyl)glycine. I 0. 025 0. 025 M200? than (N-stearoyl) sarcosine. II 0. 0125None Pass D0. (N -laur0yl) sarcosine III 0.0125 0.0125 D0. (N-stearoyl)a alanine- IV 0.0125 0.0125 Pass Do. Do IV 0.20 None Do. (N-stearoyl) Balanine V 0. 10 0. D0.

1 Primene JMR is a mixture of highly branched, aliphatic primary amineshaving the tertiary-alkylamine structure in which the primary aminonitrogen is directly attached to a tertiary carbon atom; it is composedprincipally of amines from eighteen to twenty-four carbon atoms and thepredominant portion may be represented by the formula, tCis-24Hs1-4oNHz.It contains about 23-10% non-amine material. It; is a non-viscousliquid, colorless to straw colored, insoluble in Water and does not;dissolve water to an appreciably extent. It exhibits solubility inhydrocarbon solvents and glyceride oils or fats, and in other organicliquids previously referred to under the term oleaginous vehicles.Additional physical properties are:

Formula Principally t-OmHuNH: to

t-Cu t9 2. Molecular Weight Principally 269-353. Specific Gravity, 25O.. 0.828.

Color, Varnish Scale 4-. This product designated by the trademarkPrimene J MR" is a product of Rohu & Hass Company.

oleaginous vehicle and a monoarnidocarboxylic acid having the followingempirical formula:

where R1 represents an aliphatic carboxylic acid residue of C8C24, R2represents a substituent selected from the group consisting of H, alkyl,hydroxylalkyl and phenyl group, R3 represents a substituent selectedfrom the group consisting of H, alkyl and carboxyalkyl, and n representsO or 1, and X represents H and groups capable of forming salts with thecarboxylic acid group, said monoamidocarboxylic acid being present insaid oleaginous composition in minor amounts, as little as a fraction of1% to amounts greater than 1% but in suflicient quantity to inhibit thecorrosion of said metal to :a great degree when compared with the check.

2. A rust preventive oil composition adapted for use in the presence ofwater, in systems containing metal susceptible of corrosion by water,comprising a hydrocarbon oil and a monoamidocarboxylic acid having thefollowing empirical formula:

to amounts greater than 1% but in suflicient quantity to' where? R1represents an aliphatie carboxylic acid residue OfCG-Czt, R2 representsasubstituentselected from/the. group. consisting of- H, alkyl,hydroxylalkyl-.andphenyl. group, R3 represents a substituent selectedfrom the group consisting of H, alkyl, and carboxyalkyl, and nrepresents-0 or 1, and;X represents H and groups capable of formingsalts with the carboxylic acid group, said monoamidocarboxylic acid.being, present in said oleaginous composition in, minor amounts, aslittle as a fraction of 1%toramoun-ts greater than 1% but'insutficientquantity to-inhibit thecorrosion of, said metal to a great degree whencompared with the check, and :an alkyl primary amine having 18-24 carbonatoms in sufiicient amount to solub'ilize said monoarnidocarboxylicacid.

4-. Arust preventive oil composition adapted. for use in the presence ofWater, in systems'vcontaining metal susceptibleof corrosion by water,comprising a hydrocarbon oiltanda monoamidocarboxylic acid having thefollowing empirical formula:

s R1N-(']H(CH2)COOX in where. R1 represents an aliphatic carboxylic acidresidue of (la-C24, R2 represents a substituent selected from the groupconsisting of H, alkyl, hydroxylalkyl and phenyl group, R3 represents asubstituentselected from the group consisting of H, alkyl andcarboxyalkyl, and n represents 0 or 1, and Xrepresents H and groupscapable of forming salts with the carboxylic acid group, saidmonoamidocarboxylic acid being present in said oil compositioninminoramounts, as little as a fraction of 1% to amounts greater than 1%but in sufficient quantity to inhibit thecorrosionofi said metal to agreat degree when comparedwith the check, and an alkyl primary amine.

the -,presenc,e.-ofv Water, insystem containing metal susa ceptible ofcorrosion by said Water, comprising an oleaginous vehicle and minoramounts of (N-stearoyl) sarcosine of as little as a fraction of 1% toamounts greater than 1% but in suificientquantity to inhibit thecorrosion of said metal to a great degree when compared with the check.

7. Axust-preventive composition adapted for use in the:presence oi=water, in systems containing metal susceptible of corrosion bysaidwater, comprising an oleaginous vehicle-and minoramounts of(N-lauroyl) sarcosine. of asdittle'as atraction of 1% to amounts greaterthan .-1%--but in sufficient quantity to inhibit'the corrosiomof saidmetal-to a great degree when compared with the check;

8i A1 rust preventive composition adapted .for use? in the pre-sence ofwater, in systems containing metal susceptible of"co1:rosion bysaidwater, comprising anoleaginous vehicle and minor amounts of(N-stearoy'l)" alanine ofas little as a fraction ofi l to amountsgreater than '1 but in Suificientquantity to inhibit the corrosion of'said metal to a g-reat'degree' when compared with the check;

9. A rust-preventivecompositionadapted for use in the presence of water,'in systems-containingflmetal susceptible of corrosion by said water,comprising "a'mineral oil and minor amounts of (N-stearoyl) glycine ofas little as a fraction of 1% to amounts "greater than 1% but insufiicient quantity to inhibit the corrosion of said metal to agreatdegree. when compared with the check.

10. A- rust=preventive composition. adapted'for use inthe presence ofwater, in systems. containing metal .sus-

ceptiblev of corrosion by saidwater, comprising amineral oil andminoramounts of (N-stearoyl) sarcosine ofas little as attraction of V1% toamounts greater. than. 1%. but

12. A rust-preventive composition adapted for use in theispresence ofwater, in systems containing metal susceptible of fcorrosion'bysaidwatenscomprising a mineral oil and. minor'amounts of (N=stear.oyl)alanine of as little as a-fraction of 1%:-to. amounts greater thanl%=but in-sufii'cient quantity to inhibit thecorrosion. ofsaid metal toa great :degree when compared. with the .check.

13. A rust-preventive composition adapted to use in thepresence"ofwater, in systems containing metal susceptible of'corrosionby saidwater, comprising a mineral oil and minor amounts of (N-stearoyl)glycine, as little as a fraction of 1% -but in a sufiicient quantity-toinhibit the corrosion of said metal to a great degree when compared withthe check, andalkyl-primary amines having 18-24 carbon atoms insufiicient amount to solubilize' said (N-stearoyl) glycine, inthemineral oil, the said alkyl amines being soluble in the mineral oilbut insoluble in water.

14. .A rust-preventive composition adapted to. use in the.presencesofiwater, in systems containing .metal susceptible ofcorrosion by said Water, comprising a mineral oil andminoramounts of(N-stearoyl) sarcosine, as little as a fraction of. 1% but inasufiicientquantity to inhibit thecorrosion-of said. metal to agreatdegree when compared with the check, and alkyl primary amines having18-24 carbon atoms in sufiicient amount to solubilize said (N-stearoyl).sarcosine, in the mineral oil, the said alkyl amines being soluble inthe mineral oil but insoluble in'water.

15. A rust-preventive composition adapted to use in the presenceof-water, in systems containing metal susceptible of corrosion by saidwater, comprising a mineral oil and'rninor-amounts of '(N lauroyl)sarcosine, as little as a fraction 051% but in-a sufficient quantity toinhibit thecorrosionofsaid metal toa great degree when compared withthe-check, and alkyl primary amines having 18-24 carbon atoms insufficient amount to solubilize' said (N-lauroyl) sarcosine, in themineral oil, the said:

alkyl amines being soluble in the mineral oil but insoluble in water.

16. A rust-preventive composition adapted to use in ficient'iquantityto'inhibit the corrosion of said metalito' a great degree when comparedwith the cheek, and alkyl primary amines having 1824 carbon atoms insufficient amount to solubilize said (N-stearoyl) alanine, in themineral oil, the said alkyl amines being soluble in the mineral oil butinsoluble in water.

References Cited in the file of this patent UNITED STATES PATENTS Whiteet a1 May 12, 1953

1. A RUST PREVENTIVE OLEAGINOUS COMPOSITION ADAPTED FOR USE IN THEPRESENCE OF WATER, IN SYSTEMS CONTAINING METAL SUSCEPTIBLE OF CORROSIONBY WATER, COMPRISING OLEAGINOUS VEHICLE AND A MONOAMIDOCARBOXYLIC ACIDHAVING THE FOLLOWING FORMULA: